Distributor vacuum control



May 22, 1962 J. P. COFFIN 3,036,166

DISTRIBUTOR VACUUM CONTROL Filed Oct. 14, 1960 INVENTOR. John P Cofh @IHM His Aforney United States Patent 3,036,166 DISTRIBUTOR VACUUM CGNTROL John P. Coiin, Anderson, Ind., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Filed Oct. 14, 1960, Ser. No. 62,579 12 Claims. (Cl. 200-31) This invention relates to distributors for internal cornbustion engines and more particularly to vacuum control apparatus for such distributors.

One of the objects of this invention is to provide a vacuum control arrangement for a distributor wherein means are provided for adjusting the compression of the spring of the vacuum unit and thus the point of cut-in of the unit.

Another object of this invention is to provide a Vacuum control assembly for a distributor wherein the casing of the vacuum unit that contains the diaphragm is shiftable relative to a liXed supporting bracket and wherein this bracket includes means for limiting movement of the diaphragm to thereby vary the compression of the vacuum unit spring when the casing is shifted relative to the bracket.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown.

In the drawings:

FIGURE l is a side view partly in section illustrating a distributor that is fitted with the vacuum control assembly of this invention.

FIGURE 2 is a sectional View taken along line 2 2 of FIGURE 1.

FIGURE 3 is a sectional view of a part of the vacuum control assembly of this invention and illustrating a change in position of the vacuum unit relative to the supporting bracket and a change in compression of the vacuum unit spring.

FIGURE 4 is a modified vacuum control assembly made in accordance with this invention.

Referring now to the drawings, and more particularly to FIGURE l, the reference 1li generally `designates a distributor which has a base 12 and a breaker plate 14. The base 12 supports a shaft 16 which is driven by the engine and this shaft carries the usual cam 18,. The breaker plate 14, as is well known to those skilled in the art, is shiftable relative to the base 12 and the cam 18 and carries a set of breaker contacts (not shown) which are opened yand closed by a rotation of the cam 18.

The vacuum control assembly of this invention is generally designated by reference numeral 20. This vacuum control assembly includes a vacuum unit 22 that is comprised of the sheet metal casings 24 and 26. The sheet metal casing 24 is provided with a conduit portion 28 that is connected with a source of Vacuum. A diaphragm 30 is contained within the casings 24 and 26 and is formed of a suitable flexible material such as rubber. It can be seen that the outer annular margin of the diaphragm is positioned between outer annular portions of the casings 24 and 26 with a part of the casing 26 being crimped over at 32 in order to provide a tight fit between the outer margin of the diaphragm 30 and the casings 24 and 26.

The diaphragm 30 is connected with an actuating rod 34 by means of washers 36 and 38. It can be seen that the rod 34 is headed over as at 40 in order to provide a vtight tit between the washers 38 and 36 and the part of the diaphragm fitting between these washers. The particular method of securing the actuating rod to the diaphragm 30 forms no part of this invention and may be 3,036,166 Patented May 22, 1962 tice l formed of a metal material and is spot welded or otherwise secured to the casing member 26. The coupling member 44 has a pair of axially extending slots 46 and 48 which are illustrated in FIGURE 2.

The vacuum unit 22 is supported from the base of the distributor by means of a bracket which is generally designated by reference numeral 50. The bracket 50 has a section 52 which is secured to the base 12 by suitable fasteners 54. The bracket 50 has a bent-down section 56 which is formed with an opening 58 to permit the actuating rod to move through the portion 56 of the bracket 50. In addition to these sections, the bracket 50 is formed with sections of portions 60 and 62 that straddle the coupling member 44 and which have parts that fit within the slots 46 and `48. The sections 60 and y62 of the bracket member 50 thus serve to slidably support the coupling member 44. A pair of nuts 64 and 66 are positioned on opposite sides of the sections 60 and 62 and are threaded onto the coupling member 44 as is clearly apparent from the drawings.

It can be seen that when it is desired to adjust the compression of the spring 42, the nuts 64, 66 are rotated to cause the coupling member 44 to shift relative to the fixed bracket member S0. In FIGURE 3, the coupling member 44 has been shown shifted relative to the fixed bracket member 50 and it is seen that the spring 42 has been compressed. It, of course, will be appreciated that when the coupling member 44 is shifted relative to the bracket, the casings 22 and 26 are likewise shifted with the coupling member since they are connected thereto. The diaphragm 30, however, is prevented from being shifted with the casing members gages the portion 56 of the bracket member which at all times remains fixed. It thus can be seen that the cut-in pressure of the vacuum unit may be simply adjusted by adjusting the nuts 64 and 66 to cause the coupling member 44 and the attached casings 22 and 26 -to shift relative to the bracket member 50. It will, of course, be appreciated by those skilled in the art that the rod 34 operates the breaker plate 14, the rod being connected thereto by an up-turned portion of the rod 63 which passes through a suitable opening formed in the breaker plate 14.

In the FIGURE l embodiment, the bracket member S0 is secured to the underside of the base member 12. It will be appreciated, however, that the bracket member might be secured to the top side of the base member 12 and a suitable slot provided in the base member which would receive the actuating rod 34. It will also be appreciated that the bracket member could be xed within a suitable slot formed in the base member 12 and the particular connection of the bracket member to the base member forms no part of this invention.

Referring now more particularly to FIGURE 4, a modified vacuum control assembly that has an adjustable feature is illustrated. In FIGURE 4 the reference numeral 14 once more designates a breaker plate of the distributor and the reference numeral 34 again designates the actuating rod having the atp-turned portion 68 which is positioned within an opening formed in the breaker plate 14. The vacuum unit in FIGURE 4 is designated by reference numeral 22 since it is identical in many respects with the vacuum unit 22 of FIGURES 1 and 3. In the FIGURE 4 embodiment, a coupling member 70 is provided which has external threads Iand which forms a part of the conduit for applying vacuum to the interior 22 and 26 since it encured to the other of said casing members, an opening in one of said casing members, a bracket member having a portion in alignment with said opening for limiting movement of said diaphragm in one direction under influence of said spring, said bracket member having another section forming a slidable connection with said externally threaded coupling member, vnut means threaded on said coupling member for causing said coupling member to be shifted relative to said bracket member, and an actuating rod `connected with said diaphragm and passing through the opening in one of said casing members and through the portion of said bracket member that limits movement of said diaphragm in one direction.

10. A vacuum control assembly for actuating the breaker plate of a distributor or the like comprising, a vacuum unit including casing means and a diaphragm connected thereto, a spring interposed between said casing means and said diaphragm for urging said diaphragm in one direction, a coupling member connected with said casing means having an externally threaded portion and having la passage for connecting the interior of said casing means with a source of Vacuum, a bracket member, said bracket member having a portion at least partially encircling the threaded portion of said coupling member, nut means threaded on the threaded portion of said coupling member for causing said casing means to be shifted relative to said bracket means, means on said bracket means for limiting movement of said diaphragm in one direction under the influence of said spring, and an actuating rod connected with said diaphragm.

11. A vacuum control assembly for adjusting the breaker plate of a distributor or the like comprising, support means, a vacuum unit including casing means and a diaphragm, a spring interposed between said casing means and diaphragm for urging said diaphragm in one direction, stop means fixed with respect to said support means for constantly maintaining said diaphragm at a predetermined distance from a given point on said support means when no vacuum is applied to said unit, actuating means connected with said diaphragm, and means forming an adjustable connection between said casing means and said support means whereby the compression of said spring is varied when said casing means is shifted relative to said support means without shifting said diaphragm or actuating means.

12. A vacuum control assembly for adjusting the breaker plate of la distributor or the like comprising, a support means, a vacuum unit including casing means and a diaphragm, `a spring interposed between said casing means and diaphragm for urging said diaphragm in one direction, means forming an adjustable connection between said casing means and said support means whereby said casing means may shift relative to said support means, and stop means for maintaining said diaphragm in a position fixed with respect to said support means when said casing means is moved in either direction within a predetermined range of movement, the compression of said spring `being constantly varied when said casing means is moved in either direction in said range of movement.

References Cited in the iile of this patent UNITED STATES PATENTS 2,125,367 Arthur et al. Aug. 2, 1938 2,473,170 Ostling .Tune 14, 1949 2,769,047 Hartzell et al Oct. 30, 1956 FOREIGN PATENTS 371,920 Italy June 9, 1939 

